Kim - could you and your daughter not increase your area of research to include the affordability of small solar panels with attached battery and lights? In essences they are doing the same thing as the "permanent" glow-in-the-dark materials - soaking up the sun's energy during daylight and releasing it in the evening/night time. The glow in the dark materials that actually produce light (like glowrods), rather than store it up and release it, are very expensive as they run out of usable chemical energy very quickly

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